A method and system for quantitatively grading the severity of a tobacco pepper veinal mottle virus disease

Abstract

The present application relates to a method and system for quantitatively grading the severity of tobacco pepper vein banding virus disease. The present application is aimed at a specific subtype of tobacco pepper vein banding virus in Pu'er tobacco growing areas, excavates key differential symptom combinations, establishes a six-level quantitative grading standard for disease severity, takes the proportion range of leaf curling and deformity as the core grading threshold, realizes the transition from qualitative to quantitative evaluation, in addition, establishes a symptom combination evolution model, integrates scattered characteristics as a differential path, and improves the reliability of early identification; a grading model based on multi-parameter fusion calculation is constructed, which converts experience judgment into a mathematical process, improves the objectivity, consistency and scientificity of grading, and provides a key technical basis for standard development, breeding, drug efficacy test and monitoring.

Description

Technical Field

[0001] This invention belongs to the field of plant protection technology and relates to a method and system for quantitatively grading the severity of tobacco and pepper vein mottle virus disease. Background Technology

[0002] Chili veinal mottle virus (ChiVMV) is a plant virus that poses a serious threat to Solanaceae crops such as peppers, tomatoes, and tobacco. It belongs to the genus *Potyvirus* of the family *Potyviridae*. In recent years, it has been reported in India, South Korea, Malaysia, Thailand, and parts of China (such as Sichuan, Guangxi, Hainan, Hunan, and Fujian), causing severe yield reductions. After infecting peppers, the virus triggers a series of typical symptoms: Leaf symptoms: The most typical feature is dark green stripes or mottling on the leaf veins, followed by leaf wrinkling, shrinking, and deformity. Mosaic (various shades of leaf color), yellowing, and necrosis may also occur. Fruit symptoms: The fruit may develop mottling, deformities, ring spots, or streaks of necrotic spots, affecting its commercial value.

[0003] Pepper vein mottle virus (PEV) is one of the major viruses affecting flue-cured tobacco production in the Pu'er tobacco-growing region of China in recent years, causing a severe decline in tobacco yield and quality. Currently, field identification of this disease mainly relies on empirical observation, lacking systematic research on the evolution of its symptoms. Furthermore, the assessment of PVEV severity is often limited to subjective qualitative descriptions such as "mild," "moderate," and "severe," lacking unified and quantitative grading standards. This restricts the accuracy of disease investigation, the precision of disease resistance evaluation, and the scientific assessment of control effects. In addition, there are reports of PCR-based methods for detecting PVEV in tobacco. For example, CN115873990A discloses a primer set, kit, and method for detecting tobacco viruses. Specific primer sets are designed, and multiplex PCR is used to identify or assist in the identification of whether the tested virus group contains one or more of four viruses: pepper vein mottle virus, tomato ring spot virus, tomato wilt virus, and tobacco mosaic virus. However, the aforementioned methods are cumbersome, difficult, time-consuming, and require expensive equipment, making them unsuitable for rapid field testing by grassroots plant protection workers and failing to meet the needs of large-scale disease surveys and rapid screening of disease-resistant germplasm resources. Therefore, establishing a simple, easy-to-use, and clearly quantifiable severity grading standard for pepper vein mottle virus disease, as well as developing low-cost, rapid detection methods, is of significant practical importance for field monitoring, evaluation of control effects, and disease-resistant breeding of this disease. Summary of the Invention

[0004] To address the shortcomings of existing technologies and practical needs, this invention provides a method and system for quantitatively grading the severity of tobacco and pepper vein mottle virus disease, so as to achieve standardized identification and objective assessment of the disease, and guide field monitoring, evaluation of control effects, and disease-resistant breeding.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for quantitatively grading the severity of tobacco capsicum vein mottle virus disease, the grading method comprising quantitative grading using symptom characteristics or parameter characteristics of tobacco. The tobacco symptoms include leaf curling, leaf deformity, and stunted growth. The parameter characteristics include leaf curl rate (CR), leaf deformity rate (DR), and dwarfing index (SI). CR = (Number of curled leaves / Total number of leaves in the plant) × 100%; DR = (Number of leaves with "rat-tail" tips or wrinkled leaves / Total number of leaves in the plant) × 100%; SI = (Average height of diseased plants / Average height of healthy plants in the same field) × 100%.

[0006] In this invention, targeting a specific subtype of tobacco pepper vein mottle virus in the Pu'er tobacco-growing region (this subtype, compared to ChiVMV reported in other regions, exhibits a stronger tendency for leaf vein necrosis and a more typical "rat-tail" leaf tip deformity in the Pu'er tobacco-growing region, with significant dwarfing symptoms; its near-full-length genome sequence shows 90.06%~99.26% identity with the Yunnan strain ChiVMV-YNtobacco (Genebank: JX088636.1)), the key identifying symptom combination of tobacco pepper vein mottle virus disease was clearly identified for the first time, and a six-level (0-5) quantitative grading standard for disease severity was established, innovatively... Using the specific proportion range of leaf curling and deformity as the core grading threshold, a fundamental shift from qualitative description to quantitative assessment was achieved. In addition, the temporal and spatial correlations of symptom combinations were analyzed in depth, not only statically describing the symptoms but also revealing their dynamic correlations. Grading parameters with three measurable variables—leaf curling rate, leaf deformity rate, and dwarfing index—as the core were extracted, and dispersed features were integrated into a highly specific identification path, improving the reliability of early identification. A grading model based on multi-parameter fusion calculation was constructed, transforming traditional experience-based judgment into a measurable and verifiable mathematical process, greatly improving the objectivity, consistency, and scientific nature of grading.

[0007] Optionally, the criteria for quantitative grading using the aforementioned symptom characteristics are as follows: Grade 0: No visible symptoms on the entire plant, growth is normal; Grade 1: Only the heart leaves show slight curling; the diseased plant does not show any stunting. Level 2: No more than 1 / 3 of the leaves on the entire plant are curled, and the diseased plant does not show any signs of stunting. Grade 3: One-third to one-half of the leaves on the whole plant are curled, or one to four leaves are deformed; Grade 4: 1 / 2 to 2 / 3 of the leaves of the whole plant are curled, and there are 5-8 deformed leaves among the curled leaves; Level 5: All leaves of the plant are curled, accompanied by stunted growth, and the leaves are deformed or necrotic.

[0008] Optionally, the standard for quantitative grading using the aforementioned parameter characteristics is: Level 0: CR = 0%, DR = 0%, SI ≥ 95%; Grade 1: CR < 15%, and only observed in the heart lobe, DR = 0%, SI ≥ 90%; Level 2: 15% ≤ CR < 33%, DR < 5%, SI ≥ 85%; Level 3: 33% ≤ CR < 50%, 5% ≤ DR < 15%, SI ≥ 80%; Level 4: 50% ≤ CR < 67%, 15% ≤ DR < 33%, SI < 80%; Grade 5: CR ≥ 67%, DR ≥ 33%, SI < 70%, accompanied by necrosis of the middle and lower leaves.

[0009] Secondly, the present invention provides a quantitative grading model for the severity of tobacco capsicum virus disease, wherein the input variables of the grading model include tobacco symptom characteristics or parameter characteristics, and the output variables of the model include severity level.

[0010] Optionally, the standard for quantitative grading using the symptom features in the model is: Grade 0: No visible symptoms on the entire plant, growth is normal; Grade 1: Only the heart leaves show slight curling; the diseased plant does not show any stunting. Level 2: No more than 1 / 3 of the leaves on the entire plant are curled, and the diseased plant does not show any signs of stunting. Grade 3: One-third to one-half of the leaves on the whole plant are curled, or one to four leaves are deformed; Grade 4: 1 / 2 to 2 / 3 of the leaves of the whole plant are curled, and there are 5-8 deformed leaves among the curled leaves; Level 5: All leaves of the plant are curled, accompanied by stunted growth, and the leaves are deformed or necrotic.

[0011] Optionally, the standard for quantitative classification using the parameter features in the model is: Level 0: CR = 0%, DR = 0%, SI ≥ 95%; Grade 1: CR < 15%, and only observed in the heart lobe, DR = 0%, SI ≥ 90%; Level 2: 15% ≤ CR < 33%, DR < 5%, SI ≥ 85%; Level 3: 33% ≤ CR < 50%, 5% ≤ DR < 15%, SI ≥ 80%; Level 4: 50% ≤ CR < 67%, 15% ≤ DR < 33%, SI < 80%; Grade 5: CR ≥ 67%, DR ≥ 33%, SI < 70%, accompanied by necrosis of the middle and lower leaves.

[0012] Thirdly, the present invention provides a quantitative grading system for the severity of tobacco pepper vein mottle virus disease, the grading system comprising a feature detection module and a quantitative grading module; The feature detection module is used to perform actions including: detecting tobacco symptom features or parameter features; The quantitative grading module is used to perform the following: inputting the symptom features or parameter features obtained by the feature detection module into the severity quantitative grading model of tobacco capsicum vein mottle virus disease described in the second aspect, and outputting the severity level.

[0013] This invention constructs a grading model and system based on multi-parameter fusion calculation, transforming traditional experience-based judgment into a measurable and verifiable mathematical process, greatly improving the objectivity, consistency, and scientific nature of grading. It provides a quantifiable and integrable key technological foundation for standard setting, disease-resistant breeding, precise drug efficacy testing, and intelligent monitoring. It is particularly suitable for intelligent disease monitoring systems based on image analysis, which can automatically grade diseases by training the model to identify specific symptom combinations and estimate their proportions.

[0014] Fourthly, the present invention provides the application of the method for quantitatively classifying the severity of tobacco vein mottle virus disease as described in the first aspect, the model for quantitatively classifying the severity of tobacco vein mottle virus disease as described in the second aspect, or the system for quantitatively classifying the severity of tobacco vein mottle virus disease as described in the third aspect in the prevention and control of tobacco vein mottle virus disease or in tobacco breeding.

[0015] Fifthly, the present invention provides a method for preventing and controlling tobacco capsicum vein mottle virus disease, the method comprising: controlling the disease based on the severity grading method for tobacco capsicum vein mottle virus disease described in the first aspect, the severity grading model for tobacco capsicum vein mottle virus disease described in the second aspect, or the severity grading system for tobacco capsicum vein mottle virus disease described in the third aspect, by obtaining the severity level result. For level 0, prevention is key; cut off transmission routes and implement agricultural control measures: promptly remove weeds in and around the field (such as black nightshade from the Solanaceae family and beggar-ticks and tufts of grass from the Asteraceae family) to reduce initial sources of infection; increase the application of well-rotted organic fertilizer and phosphorus and potassium fertilizer to cultivate strong seedlings and improve the tobacco plants' own resistance; promote the use of silver-gray mulch to repel aphids; physical / biological control: hang yellow sticky insect boards in tobacco fields or seedling sheds to monitor and kill transmission vectors (such as peach aphids and cotton aphids); when aphid-infested plants are found in the field, spray aphid insecticides (such as matrine aqueous solution (content can be 0.3%) or imidacloprid wettable powder (content can be 10%)) to control aphid populations; For Level 1, early intervention is crucial to inhibit virus proliferation and transmission. Chemical control: Immediately spray virus inactivators (including ningnanmycin aqueous solution or amino oligosaccharide aqueous solution, such as 8% ningnanmycin aqueous solution (800x dilution) or 2% amino oligosaccharide aqueous solution (600x dilution), etc. Spraying can include two consecutive applications, 7 days apart, focusing on new leaves and the heart leaves); Interrupting transmission: In conjunction with aphid control, spray aphid insecticides (such as 20% acetamiprid soluble powder (3000x dilution) or 50% imidacloprid wettable powder (2000x dilution)). For level 2, control the disease and prevent its spread: Strengthen prevention and control: Spray virus inactivating agents (such as ningnanmycin or amino oligosaccharides), or spray virus inactivating agents mixed with inducers (3% hypersensitive protein microparticles (diluted 1000 times)) to induce systemic resistance in tobacco plants; Nutritional regulation: Foliar spray brassinolide (such as 0.01% brassinolide (2000 times)) + potassium dihydrogen phosphate (content can be 0.2%) to alleviate growth inhibition caused by viral diseases and enhance the repair ability of tobacco plants; For level 3, implement combined measures to mitigate losses, remove diseased plants with an estimated yield loss exceeding 70%, and disinfect the affected areas (by applying quicklime); use a combination of pesticides: spray the remaining tobacco leaves with antiviral agents and insecticides, for example: use 8% Ningnanmycin aqueous solution + 20% acetamiprid + 0.01% brassinolide + 0.2% potassium dihydrogen phosphate, diluted with water and sprayed evenly, focusing on the middle and upper leaves; field management: remove lower, severely diseased, and old leaves, improve field ventilation and light penetration, and irrigate (e.g., frequent small irrigations) to avoid drought exacerbating the disease.

[0016] For level 4, control yield loss and prevent secondary damage: Remove severely diseased plants: Remove severely diseased plants that have no economic value (estimated yield loss exceeds 70%) in a timely manner and destroy them centrally; Select broad-spectrum antiviral agents to protect uninfected or mildly symptomatic leaves and slow down the necrosis process. 25% copper guanidine·acetate (500 times dilution) can be used. Strictly prevent complications: Diseased plants have weak resistance and are susceptible to fungal diseases (such as red spot disease). Prevention should be combined with fungicides (such as 40% sclerotinia sclerotinia). For level 5, control the source of infection: immediately remove the affected plants. These plants have no economic value and are the most dangerous source of infection in the field; they must be completely removed immediately and disposed of outside the field. Disinfect the affected planting holes: disinfect the soil around the holes where the diseased plants were removed (e.g., by applying quicklime or irrigating with a potassium permanganate solution (1000 times dilution)). Focus on surrounding control: immediately apply concentrated, high-intensity pesticide protection to healthy plants around the diseased plant and to plants with levels 1-4 of infection, using a combination of ningnanmycin (e.g., 8% ningnanmycin) + insecticide (e.g., 20% acetamiprid) + nutrient (e.g., amino acid water-soluble fertilizer) to strictly prevent further spread of the virus through agricultural operations or aphids.

[0017] In a sixth aspect, the present invention provides an electronic device comprising one or more processors and a memory for storing executable instructions, characterized in that the one or more processors are configured to invoke the executable instructions stored in the memory to implement the function of the tobacco capsicum vein mottle virus disease severity quantitative grading system described in the third aspect.

[0018] In a seventh aspect, the present invention provides a computer-readable storage medium having stored thereon computer program instructions, characterized in that, when the computer program instructions are executed by a processor, they implement the function of the tobacco capsicum vein mottle virus disease severity quantitative grading system described in the third aspect.

[0019] Compared with the prior art, the present invention has at least the following beneficial effects: This invention targets a specific subtype of tobacco vein mottle virus in the Pu'er tobacco-growing area, identifying key symptom combinations for identifying the disease and establishing a six-level (0-5) quantitative grading standard for disease severity. It innovatively uses the specific proportion range of leaf curling and malformation as the core grading threshold, achieving a fundamental shift from qualitative description to quantitative assessment. The standard is clearly defined, the indicators are objective, and it facilitates rapid and accurate interpretation in the field, greatly improving the standardization level and scientific value of disease investigation and assessment. It provides a reliable technical tool for related scientific research, breeding, and precision control. Furthermore, by establishing a symptom combination evolution model, dispersed characteristics are integrated into a highly specific identification path, improving the reliability of early identification. A grading model based on multi-parameter fusion calculation is constructed, transforming traditional experience-based judgment into a measurable and verifiable mathematical process, greatly improving the objectivity, consistency, and scientific rigor of the grading. This provides a quantifiable and integrable key technical foundation for standard setting, disease-resistant breeding, precision efficacy testing, and intelligent monitoring. Attached Figure Description

[0020] Figure 1This is a schematic diagram of the symptom evolution model and corresponding severity levels of Tobacco Varnish Mottle Virus Disease (ChiVMV-PE) in an embodiment of the present invention. Using a bottom-up timeline as a baseline, the diagram clearly shows the dynamic evolution path of typical symptoms in tobacco plants from the initial stage of infection with ChiVMV-PE, to gradual onset of disease, and finally to a severe state. Each stage of symptom evolution is clearly marked with its corresponding disease severity level. The horizontal axis of the diagram includes three core quantitative parameters: leaf curl rate (CR), leaf deformity rate (DR), and dwarfing index (SI). The specific numerical range of each parameter corresponds one-to-one with the aforementioned disease severity levels, realizing a direct correlation between disease symptoms and quantitative parameters. This diagram intuitively demonstrates the technical concept of the present invention, which transforms the dynamic and complex composite symptoms of Tobacco Varnish Mottle Virus Disease (ChiVMV-PE) into a standardized, quantifiable, and accurately identifiable disease severity grading standard, providing an intuitive visual basis for rapid and accurate determination of disease severity. Detailed Implementation

[0021] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0022] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased from legitimate channels.

[0023] The purpose of this invention is to provide a standardized symptom description of tobacco capsicum vein mottle virus disease and a corresponding quantitative method for grading disease severity, in order to solve the problems of subjective diagnosis and vague assessment in the prior art. The typical symptom characteristics of tobacco capsicum vein mottle virus disease are as follows: Leaf morphology and color symptoms: The leaves of infected tobacco plants turn yellow and turn pale green, the veins are clearly mottled, and the leaf morphology changes significantly, such as the leaf margins curling downward, the leaves not spreading properly, wrinkling and twisting deformed, and the leaf tips becoming thinner and sharper, resembling "rat tail" or "shoe tip". Severely diseased leaves become hard in texture. Overall symptoms of the plant: The growth of diseased plants is inhibited, manifested by shortened internodes and stunting. As the disease worsens, the leaves turn yellow and die sequentially from bottom to top, eventually resulting in severe curling, deformity or necrosis of all leaves.

[0024] The disease severity grading method uses a single plant as the investigation unit and classifies the disease severity into levels 0 to 5 based on the degree and extent of leaf curling, deformity, and plant stunting. The specific standards are as follows: Grade 0: No visible symptoms on the entire plant, growth is normal; Grade 1: Only the heart leaves (the uppermost new leaves) show slight curling, and the diseased plant as a whole does not show obvious stunting. Grade 2: Up to one-third (1 / 3) of the leaves of the whole plant are curled, and the diseased plant is not obviously stunted; Grade 3: One-third to one-half (1 / 3 to 1 / 2) of the leaves of the whole plant are curled, or 1-4 leaves are deformed; Grade 4: One-half to two-thirds (1 / 2 to 2 / 3) of the leaves on the whole plant are curled, and about 5-8 of them are deformed; Level 5: All leaves of the plant are curled, accompanied by obvious stunting of the plant, and the leaves are severely deformed or have become necrotic.

[0025] Furthermore, such as Figure 1 As shown, based on the above standardized symptom descriptions, the temporal and spatial correlations of symptom combinations were analyzed. After viral infection, symptoms typically follow an evolutionary pattern of "clear veins or mottling in the heart leaf → downward curling of leaf margins → leaf wrinkling and restricted expansion → elongated leaf tips exhibiting a typical 'rat-tail' shape → deepening of veins and hardening of leaves → symptom expansion from top to bottom accompanied by plant dwarfing." A grading method was developed with three measurable variables as its core: leaf curl rate (CR), leaf deformity rate (DR), and dwarfing index (SI), specifically defined as: Leaf curl rate (CR) = (Number of curled leaves / Total number of leaves in the whole plant) × 100%; Leaf deformity rate (DR) = (Number of leaves with "rat-tail" tips or wrinkled leaves / Total number of leaves in the plant) × 100%; Dwarfing Index (SI) = (Average height of diseased plants / Average height of healthy plants in the same field) × 100%.

[0026] Establish the following six-level quantitative standards: Level 0: CR = 0%, DR = 0%, SI ≥ 95%; Grade 1: CR < 15%, and only observed in the heart lobe, DR = 0%, SI ≥ 90%; Level 2: 15% ≤ CR < 33%, DR < 5%, SI ≥ 85%; Level 3: 33% ≤ CR < 50%, 5% ≤ DR < 15%, SI ≥ 80%; Level 4: 50% ≤ CR < 67%, 15% ≤ DR < 33%, SI < 80%; Grade 5: CR ≥ 67%, DR ≥ 33%, SI < 70%, accompanied by necrosis of the middle and lower leaves.

[0027] By introducing explicit percentage thresholds and multiple condition judgments, the evaluation achieves objectivity and refinement.

[0028] Based on the above quantitative grading results, targeted prevention and control plans can be designed: For level 0, prevention is key; cut off transmission routes and implement agricultural control measures: promptly remove weeds in and around the field (such as black nightshade from the Solanaceae family and beggar-ticks and tufts of grass from the Asteraceae family) to reduce initial sources of infection; increase the application of well-rotted organic fertilizer and phosphorus and potassium fertilizer to cultivate strong seedlings and improve the tobacco plants' own resistance; promote the use of silver-gray mulch to repel aphids; physical / biological control: hang yellow sticky insect boards in tobacco fields or seedling sheds to monitor and kill transmission vectors (such as peach aphids and cotton aphids); when aphid-infested plants are found in the field, spray aphid insecticides (such as matrine aqueous solution (content can be 0.3%) or imidacloprid wettable powder (content can be 10%)) to control aphid populations; For Level 1, early intervention is crucial to inhibit virus proliferation and transmission. Chemical control: Immediately spray with a virus inactivator (such as 8% ningnanmycin aqueous solution (800x dilution) or 2% amino oligosaccharide aqueous solution (600x dilution), etc. Spraying can include two consecutive applications, 7 days apart, focusing on new leaves and the heart leaves; Interrupting transmission: In conjunction with aphid control, spray with aphid insecticides (such as 20% acetamiprid soluble powder (3000x dilution) or 50% imidacloprid wettable powder (2000x dilution)). For level 2, control the disease and prevent its spread: Strengthen prevention and control: Spray virus inactivating agents (such as ningnanmycin or amino oligosaccharides), or spray virus inactivating agents mixed with inducers (3% hypersensitive protein microparticles (diluted 1000 times)) to induce systemic resistance in tobacco plants; Nutritional regulation: Foliar spray brassinolide (such as 0.01% brassinolide (2000 times)) + potassium dihydrogen phosphate (content can be 0.2%) to alleviate growth inhibition caused by viral diseases and enhance the repair ability of tobacco plants; For level 3, implement combined measures to mitigate losses, remove diseased plants with an estimated yield loss exceeding 70%, and disinfect the affected areas (by applying quicklime); use a combination of pesticides: spray the remaining tobacco leaves with antiviral agents and insecticides, for example: use 8% Ningnanmycin aqueous solution + 20% acetamiprid + 0.01% brassinolide + 0.2% potassium dihydrogen phosphate, diluted with water and sprayed evenly, focusing on the middle and upper leaves; field management: remove lower, severely diseased, and old leaves, improve field ventilation and light penetration, and irrigate (e.g., frequent small irrigations) to avoid drought exacerbating the disease.

[0029] For level 4, control yield loss and prevent secondary damage: Remove severely diseased plants: Remove severely diseased plants that have no economic value (estimated yield loss exceeds 70%) in a timely manner and destroy them centrally; Select broad-spectrum antiviral agents to protect uninfected or mildly symptomatic leaves and slow down the necrosis process. 25% copper guanidine·acetate (500 times dilution) can be used. Strictly prevent complications: Diseased plants have weak resistance and are susceptible to fungal diseases (such as red spot disease). Prevention should be combined with fungicides (such as 40% sclerotinia sclerotinia). For level 5, control the source of infection: immediately remove the affected plants. These plants have no economic value and are the most dangerous source of infection in the field; they must be completely removed immediately and disposed of outside the field. Disinfect the affected planting holes: disinfect the soil around the holes where the diseased plants were removed (e.g., by applying quicklime or irrigating with a potassium permanganate solution (1000 times dilution)). Focus on surrounding control: immediately apply concentrated, high-intensity pesticide protection to healthy plants around the diseased plant and to plants with levels 1-4 of infection, using a combination of ningnanmycin (e.g., 8% ningnanmycin) + insecticide (e.g., 20% acetamiprid) + nutrient (e.g., amino acid water-soluble fertilizer) to strictly prevent further spread of the virus through agricultural operations or aphids.

[0030] Example 1 This embodiment performs quantitative grading of the severity of tobacco capsicum vein mottle virus disease.

[0031] During the mid-to-late stages of tobacco field growth, a general survey or special investigation of diseases is conducted. First, based on typical symptoms (especially vein mottling, downward curling of leaf margins, and rat-tail-like deformities of leaf tips), pepper vein mottling virus-infected plants are preliminarily identified. After confirmation, each diseased plant is independently assessed: carefully observe all leaves, estimate the proportion of curled and deformed leaves, and determine the degree of plant stunting. Strictly classify according to the six-level quantitative standard. According to the grading standard: if no visible symptoms are observed, it is classified as Grade 0; if only slightly curled top leaves are observed, it is classified as Grade 1; if about one-third of the leaves are curled but the plant height is normal, it is classified as Grade 2; if the estimated proportion of curled leaves is about 40% of the total leaves and no obvious stunting is observed, it is classified as Grade 3; if the curling proportion reaches 60% and some leaves are deformed, it is classified as Grade 4; if all leaves of the plant are curled, deformed, and stunted, it is classified as Grade 5. This method is applicable to field disease surveys, screening tests of disease-resistant varieties, and evaluation of the efficacy of control agents, ensuring the consistency and comparability of survey results from different personnel and locations.

[0032] Example 2 This embodiment performs quantitative grading of the severity of tobacco capsicum vein mottle virus disease.

[0033] The first step is identification: Based on the "temporal and spatial correlation of symptom combinations," plants in the field that meet the criteria of "mottled heart leaves with downward curling, and at least one leaf with a 'rat-tail' tip" are identified and marked. The second step is measurement and calculation: For the marked diseased plants, the total number of leaves, the number of curled leaves, and the number of deformed leaves are counted, plant height is measured, and CR, DR, and SI values ​​are calculated. The third step is grading: The calculated CR, DR, and SI values ​​are substituted into the aforementioned six-level quantitative standard for judgment. For example, a tobacco plant with CR=40%, DR=8%, and SI=82% is classified as grade 3. This method is particularly suitable for intelligent disease monitoring systems based on image analysis. By training a model to identify specific symptom combinations and estimate their proportions, automatic grading can be achieved.

[0034] Example 3 This embodiment is based on a symptom evolution model for early diagnosis.

[0035] This embodiment aims to verify the ability of the method of the present invention to identify ChiVMV-PE in the early stage of tobacco growth (from the clump stage to the vigorous growth stage), when the symptoms are often atypical and easily confused with physiological leaf curling.

[0036] In the Pu'er tobacco-growing area, tobacco plants with prominent veins or slight mottling on the central leaves, accompanied by slight downward curling of the leaf margins but without obvious "rat-tail" deformities, were observed. At this stage, instead of immediate grading, the marked diseased plants were observed for 3-5 consecutive days. Based on the symptom progression pattern established according to this invention—"prominent veins or mottling on the central leaves → downward curling of leaf margins → leaf wrinkling and obstructed extension"—if the downward curling symptoms do not subside during the observation period, and the previously curled leaves begin to show slight obstruction of extension (uneven leaf surface), ChiVMV-PE infection is highly suspected. Following the symptom characteristics described in this invention, a preliminary grade 1 diagnosis can be made, and early intervention (antiviral agents + aphid control) can be implemented. This is approximately 5-7 days earlier than simply relying on visual observation of the "rat-tail" deformity (which usually takes until grade 2-3), providing valuable time for early and thorough treatment. In the experimental fields where this method was applied, compared with the control fields that relied solely on typical symptoms for identification, the first application of pesticides was brought forward by an average of 6 days, and the rate of diseased plants at level 3 or above was reduced by about 30% in the later stages. This demonstrates the significant advantages of the symptom evolution model in improving the reliability of early identification and guiding early prevention and control.

[0037] Example 4 This embodiment utilizes a quantitative grading model to evaluate the efficacy of pesticides.

[0038] This embodiment is used to demonstrate the quantitative evaluation advantages of the present invention in field efficacy trials of antiviral agents.

[0039] In tobacco fields with uniform disease incidence in the Pu'er tobacco region, three treatments were set up: Treatment A (test agent, 8% Ningnanmycin), Treatment B (5% amino oligosaccharide aqueous solution), and Treatment C (blank control). Each treatment was replicated three times. Surveys were conducted before application, 7 days after application, and 14 days after application. Survey and calculation: For each survey, 50 plants were randomly selected from each plot. The investigators used the parameter characteristic grading standard of this invention to record the CR, DR, and SI of each plant, and automatically determined the severity level of each plant according to the six-level quantitative standard. Data analysis: The disease index (DI) of each treatment was calculated. The formula is: Disease Index (DI) = Σ(Number of diseased plants at each level × Representative value at each level) / (Total number of plants surveyed × Highest level representative value) × 100. Then the control efficacy of each treatment was calculated. Control efficacy (%) = (DI of control area - DI of treatment area) / DI of control area × 100%. Through parametric grading, the disease severity indices for treatments A, B, and C were 12.5, 25.6, and 48.3, respectively. The calculated efficacy of treatment A was 74.1%, significantly higher than that of treatment B (47.0%). The results show that traditional qualitative grading (mild, moderate, severe) cannot distinguish this statistical difference between treatments A and B. This invention, by providing continuous and accurate quantitative data, significantly improves the sensitivity and scientific rigor of drug efficacy evaluation, enabling more precise screening of highly effective drugs.

[0040] In summary, this invention targets a specific subtype of tobacco vein mottle virus in the Pu'er tobacco-growing area, identifies key identifying symptom combinations for the disease, and establishes a six-level (0-5) quantitative grading standard for disease severity. It innovatively uses the specific proportion range of leaf curling and malformation as the core grading threshold, achieving a fundamental shift from qualitative description to quantitative assessment. The standard is clearly defined, the indicators are objective, and it facilitates rapid and accurate interpretation in the field, greatly improving the standardization level and scientific value of disease investigation and assessment. It provides a reliable technical tool for related scientific research, breeding, and precision control. Furthermore, by establishing a symptom combination evolution model, dispersed characteristics are integrated into a highly specific identification path, improving the reliability of early identification. A grading model based on multi-parameter fusion calculation is constructed, transforming traditional experience-based judgment into a measurable and verifiable mathematical process, greatly improving the objectivity, consistency, and scientific rigor of the grading. This provides a quantifiable and integrable key technical foundation for standard setting, disease-resistant breeding, precision efficacy testing, and intelligent monitoring.

[0041] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for quantitatively grading the severity of tobacco capsicum vein mottle virus disease, characterized in that, The grading method includes quantitative grading using symptom characteristics or parameter characteristics of tobacco. The tobacco symptoms include leaf curling, leaf deformity, and stunted growth. The parameter characteristics include leaf curl rate (CR), leaf deformity rate (DR), and dwarfing index (SI). CR = (Number of curled leaves / Total number of leaves in the plant) × 100%; DR = (Number of leaves with "rat-tail" tips or wrinkled leaves / Total number of leaves in the plant) × 100%; SI = (Average height of diseased plants / Average height of healthy plants in the same field) × 100%.

2. The method for quantitatively grading the severity of tobacco capsicum vein mottle virus disease according to claim 1, characterized in that, The criteria for quantitative grading using the aforementioned symptom characteristics are as follows: Grade 0: No visible symptoms on the entire plant, growth is normal; Grade 1: Only the heart leaves are curled, and the diseased plant does not show any signs of stunting. Level 2: No more than 1 / 3 of the leaves on the entire plant are curled, and the diseased plant does not show any signs of stunting. Grade 3: One-third to one-half of the leaves on the whole plant are curled, or one to four leaves are deformed; Grade 4: 1 / 2 to 2 / 3 of the leaves of the whole plant are curled, and there are 5-8 deformed leaves among the curled leaves; Level 5: All leaves of the plant are curled, accompanied by stunted growth, and the leaves are deformed or necrotic.

3. The method for quantitatively grading the severity of tobacco capsicum vein mottle virus disease according to claim 1 or 2, characterized in that, The standard for quantitative grading using the aforementioned parameter characteristics is as follows: Level 0: CR = 0%, DR = 0%, SI ≥ 95%; Grade 1: CR < 15%, and only observed in the heart lobe, DR = 0%, SI ≥ 90%; Level 2: 15% ≤ CR < 33%, DR < 5%, SI ≥ 85%; Level 3: 33% ≤ CR < 50%, 5% ≤ DR < 15%, SI ≥ 80%; Level 4: 50% ≤ CR < 67%, 15% ≤ DR < 33%, SI < 80%; Grade 5: CR ≥ 67%, DR ≥ 33%, SI < 70%, accompanied by necrosis of the middle and lower leaves.

4. A quantitative grading model for the severity of tobacco capsicum vein mottle virus disease, characterized in that, The input variables of the grading model include tobacco symptom characteristics or parameter characteristics, and the output variables of the model include severity levels.

5. The quantitative grading model for the severity of tobacco capsicum vein mottle virus disease according to claim 4, characterized in that, The standard for quantitative grading using the symptom characteristics in the model is as follows: Grade 0: No visible symptoms on the entire plant, growth is normal; Grade 1: Only the heart leaves are curled, and the diseased plant does not show any signs of stunting. Level 2: No more than 1 / 3 of the leaves on the entire plant are curled, and the diseased plant does not show any signs of stunting. Grade 3: One-third to one-half of the leaves on the whole plant are curled, or one to four leaves are deformed; Grade 4: 1 / 2 to 2 / 3 of the leaves of the whole plant are curled, and there are 5-8 deformed leaves among the curled leaves; Level 5: All leaves of the plant are curled, accompanied by stunted growth, and the leaves are deformed or necrotic. Optionally, the standard for quantitative classification using the parameter features in the model is: Level 0: CR = 0%, DR = 0%, SI ≥ 95%; Grade 1: CR < 15%, and only observed in the heart lobe, DR = 0%, SI ≥ 90%; Level 2: 15% ≤ CR < 33%, DR < 5%, SI ≥ 85%; Level 3: 33% ≤ CR < 50%, 5% ≤ DR < 15%, SI ≥ 80%; Level 4: 50% ≤ CR < 67%, 15% ≤ DR < 33%, SI < 80%; Grade 5: CR ≥ 67%, DR ≥ 33%, SI < 70%, accompanied by necrosis of the middle and lower leaves.

6. A quantitative grading system for the severity of tobacco capsicum vein mottle virus disease, characterized in that, The grading system includes a feature detection module and a quantitative grading module; The feature detection module is used to perform actions including: detecting tobacco symptom features or parameter features; The quantitative grading module is used to perform the following: inputting the symptom features or parameter features obtained by the feature detection module into the severity quantitative grading model of tobacco capsicum vein mottle virus disease as described in claim 4 or 5, and outputting the severity level.

7. The application of the method for quantitatively grading the severity of tobacco and capsicum vein mottle virus disease according to any one of claims 1-3, the model for quantitatively grading the severity of tobacco and capsicum vein mottle virus disease according to claim 4 or 5, or the system for quantitatively grading the severity of tobacco and capsicum vein mottle virus disease according to claim 6 in the prevention and control of tobacco and capsicum vein mottle virus disease or in tobacco breeding.

8. A method for controlling tobacco and pepper vein mottle virus disease, characterized in that, The prevention and control method includes: conducting prevention and control based on the severity level results obtained from the severity quantitative grading method for tobacco capsicum vein mottle virus disease according to any one of claims 1-3, the severity quantitative grading model for tobacco capsicum vein mottle virus disease according to claim 4 or 5, or the severity quantitative grading system for tobacco capsicum vein mottle virus disease according to claim 6. For level 0, implement agricultural control measures: remove weeds in and around the field to reduce the initial source of infection; increase the application of well-rotted organic fertilizer and phosphorus and potassium fertilizer to cultivate strong seedlings; promote the use of silver-gray mulch to repel aphids; physical / biological control: hang yellow sticky insect boards in tobacco fields or seedling sheds to monitor and kill the vectors; when aphid-infested plants are found in the field, spray aphid insecticides. For Level 1, early intervention is carried out to inhibit virus proliferation and spread, including chemical control: spraying virus inactivators; and cutting off transmission: combining aphid control with spraying aphid insecticides. For level 2, strengthen prevention and control measures: spray with virus inactivating agent, or spray with virus inactivating agent mixed with inducer; adjust nutrition: foliar spray with brassinolide and potassium dihydrogen phosphate; For level 3, remove diseased plants with an estimated yield loss of more than 70% and disinfect the affected planting holes; use a combination of pesticides: spray the remaining tobacco leaves with antiviral agents and insecticides; field management: remove severely diseased old leaves from the lower part of the tobacco plant, improve ventilation and light penetration in the field, irrigate, and avoid drought; For level 4, remove severely diseased plants: remove diseased plants with an estimated yield loss of more than 70%, and spray the remaining tobacco leaves with broad-spectrum antiviral agents and fungicides; For level 5, remove the affected tobacco plants, disinfect the affected area, and spray the remaining tobacco plants with ningnanmycin, insecticides, and nutrients.

9. An electronic device comprising one or more processors and a memory for storing executable instructions, characterized in that, The one or more processors are configured to invoke executable instructions stored in the memory to implement the function of the tobacco capsicum vein mottle virus disease severity grading system of claim 6.

10. A computer-readable storage medium having computer program instructions stored thereon, characterized in that, When the computer program instructions are executed by the processor, they implement the function of the severity grading system for tobacco capsicum vein mottle virus disease as described in claim 6.

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